Swimming pool staircase



FIG. 1 is a front and right side elevational perspective of a swimming pool staircase, showing our new design;

FIG. 2 is a front and left side elevational perspective thereof,

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a right side plan view thereof, the left side being a mirror view thereof. 

We claim, the ornamental design for a swimming pool staircase, as shown and described. 